A ski consists of a body or carrier, a running surface or sole and steel edges at both sides of the running surface. The ski body is made up of layers or sheets of wood, steel and/or plastic, the running surface is formed by a plastic coat, and the steel edges are either bars of rectangular cross section inserted at both sides of the running surface or metal sectional material with a sharp outer edge embedded in the plastic.
The running surfaces or soles of known skis have so-called running grooves to improve the tracking properties of the ski. In most cases a semi-circular fluting is provided which extends in the middle of the sole, in other cases, e.g., with jumping skis a plurality of parallel flutings are provided in the sole. Moreover, it is known to design the running groove as a broad channel with rectangular cross section. Finally, ski edges are known which comprise skids or have an edge profile that tapers outwardly, as seen in cross section, or have a hollow polished or ground section similar to skates. It is the purpose of these measures to improve the ski such that it will better maintain the direction determined by the skier, in other words hold the track better than is possible with smooth running surfaces.
An essential factor in considering the usefulness of a ski is the coordination between the steel edges and the elasticity of the ski. The steel edges make it possible to bring the ski into engagement with the ground during a change of direction, i.e., when swinging or turning so that the skier can dominate the radial drift or sideslip during a swing, in other words keep it as small as possible. The elastic properties of the ski should be chosen such that the steel edge will engage the ground approximately uniformly over its entire length upon a turn. This engagement of the steel edges during swinging or turning is necessary especially on trails or runs, above all on hard runs. With all the known skis only one steel edge will engage the ground in a turn during which the ski is slightly tilted inwardly. Any attempt made so far at improving this engagement was always directed at improving the elasticity of the ski.